Police said the attacks lasted for five hours and all the assailants had been killed by around 3 pm local time.

Twelve people were killed and several others injured as gunmen and suicide bombers stormed Iran’s parliament and the Mausoleum of Imam Khomeini in Tehran on Wednesday.

The Islamic State group claimed the responsibility of the attack, reported AFP. Iraq’s emergency services said 12 people had died in the two attacks and 39 people were injured.

Police said the attacks lasted for five hours and all the assailants had been killed by around 3 pm local time. ISIS released a video of the attackers, holed up in parliamentary office buildings, via Amaq, its propaganda agency.

Four gunmen had burst into the parliament complex in Tehran mid-morning and killed a security guard and one other person, reported ISNA news agency. An interior ministry official said the men, dressed as women, made their way through the visitor’s entrance. Parliament was in session when the attack started and continued normally despite the attack, according to Mehr.

At almost the same time, a team of three or four assailants entered the grounds of the mausoleum of Ayatollah Ruhollah Khomeini. The assailants killed a gardener and wounded several other people. Two attackers were arrested and the third one blew himself up by detonating his vest, Mehr reported. Officials told the news agency that an explosive device was defused near the shrine.

This is the first attack carried out by the extremist Sunni group inside the Shi’ite Muslim country, according to Reuters.